Recirculating system for a self-contained sewage unit



Nov. 18, 1969 R, c HELKE' ET AL 3,478,690

RECIRCULATING SYSTEM FOR A SELF-CONTAINED SEWAGE UNIT Filed Dec. 28,1967 3 Sheets-Sheet Nov. 18, 1969 R. c. HELKE ET AL 3,478,690

RECIRCULATING SYSTEM FOR A SELF-CONTAINED SEWAGE UNIT Filed Dec. 28,1967- :5 Sheets-Sheet rs United States Patent 3,478,690 RECIRCULATINGSYSTEM FOR A SELF- CONTAINED SEWAGE UNIT Robert C. Helke, Dayton, andWayne E. Sturgeon, Xenia, Ohio, assignors to Koehler-Dayton, Inc.,Dayton, Ohio, a corporation of Ohio Filed Dec. 28, 1967, Ser. No.694,322 Int. Cl. F04d 3/02; F04b 21/00; E03d 11/10 US. Cl. 10393 18Claims ABSTRACT OF THE DISCLOSURE A recirculating system having an axialflow pump with an upper outlet and a lower inlet formed by a bell-shapedditfusor; a slotted filter supported for rotation around the ditfusorand having a plurality of axially spaced peripheral slots each receivinga cleaning plate. A reversible motor connected to one shaft for rotatingthe filter in opposite directions and to another shaft supporting twoaxial flow impellers each having a single vane providing surfacesextending transversely in opposite directions relative to the shaft. Oneof the vanes positioned adjacent the diffusor and the other adjacent theoutletand cooperating to produce a single direction, axial flow ofliquid within the chamber regardless of the direction of rotation of themotor.

BACKGROUND OF THE INVENTION In a self-contained sewage unit as disclosedin US. Patent No. 3,067,433, assigned to the assignee of the presentinvention, a recirculating pump system is employed for flushing the bowlinto a storage tank and in-. corporates an axial flow pump having avertically extending cylindrical pumping chamber with a lower axiallyextending inlet and an upper radially extending outlet. An axial flowscrew-type impeller is positioned within the pumping chamber and issupported by the lower end portion of a vertically extending shaftconnected to a drive motor.

Surrounding the lower inlet of the pump is a cupshaped filter which isconstructed by a series of rings spaced to define peripheral slotstherebetween. The filter is driven by an auxiliary drive shaft connectedto the drive motor which is adapted to be momentarily reversed at thebeginning of each cycle so that the filter slots are eifectively cleanedby a series of stationary scraper or wiper plates projecting inwardlyinto the slots. It is also possible to hold the filter body stationaryand rotate the wipers, as in US. Patent No. 3,342,341.

It has been found that an axial flow pump is ideally suited for arecirculating system for a self-contained sewage unit as it provides ahigh volume flow at a relatively low pressure and is especially quietduring operation. As disclosed in the above patent, one means forassuring effective cleaning of the filter slots is to reversemomentarily the direction of rotation of the filter at the beginning ofeach cycle of operation. It has also been proposed to alternate thedirection of rotation of the motor and filter during successive cycles.In the latter case, however, the conventional screw-type axial flowimpeller will not pump liquid from the inlet to the outlet when the iceSUMMARY 01 THE INVENTION The present invention is directed to animproved recirculating system for a self-contained sewage unit and as aprimary feature incorporates a novel axial fiowimpeller which iseffective to pump liquid always in one direction regardless of itsdirection of rotation. Thus the impeller of the invention isparticularly suited for use in a sewage unit having a drive motor whichreverses its direction of rotation in successive cycles for purposes ofcleaning the filter, and in addition, provides the desirable features ofquiet operation and a high volume low pressure flow of an axial fiowpump. A number of different forms of such an impeller are disclosed.

The recirculating system of the invention is also capable of use with alow head of liquid surrounding the filter without producing aeration ofair binding of the pumping chamber, which commonly occurs with a lowhead of liquid as a result of cavitation. This latter feature isprovided primarily by the use of ditfusor vanes located at the lower endof the pumping chamber adjacent the inlet of the axial fiow pump.

In accordance with a preferred embodiment of the invention, therecirculating system incorporates two axially spaced impellers mountedon the lower end portion of the impeller drive shaft, with each impellerincluding a single radially projecting vane having generally atriangular cross-sectional configuration. The axially spaced vanes aredisposed from each other relative to the shaft with the lower vanedisposed adjacent the diifusor vanes and the upper vane adjacent theoutlet.

More specific features and advantages of the recirculating systemconstructed in accordance with the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axial section view of arecirculating system constructed in accordance with the invention;

FIG. 2 is a section view taken generally along the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary view taken generally along the line 3-3 of FIG.1;

FIG. 4 is a fragmentary section taken generally along the line 44 ofFIG. 1;

FIG. 5 is an elevational view of a single vane impeller similar to theimpeller shown in FIGS. 1-4 but having a modified vane configuration;

FIG. 6 is a perspective view of a twin fixed vane impeller constructedin accordance with the invention;

FIG. 7 is a perspective view of a twin tilt vane impeller constructed inaccordance with the invention;

FIG. 8 is an elevational view of a twin flexible vane impellerconstructed in accordance with the invention;

FIGS. 9 and 10 are elevational views of another twin fixed vane impellershowing a modification of the impeller of FIG. 6;

FIG. 11 is an elevational view of another single fixed vane impellershowing a modification of the impeller illustrated in FIGS. 1-4; and

FIG. 12 is a fragmentary axial section of the lower portion of therecirculating system showing a modification of the pump inlet anddiifusor vanes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, therecirculating system shown in FIG. 1 is similar to the systems disclosedin the above identified US. patents. Specifically, the system of theinvention incorporates a housing 1-0 which is preferably molded from arigid plastic material, and includes an upper portion 12 defining achamber 13. The upper portion 12 includes an outwardly projecting flange14 attached to the underneath surface of a generally flat cover member15 by a series of peripherally spaced screws 16 threaded into a backupmounting ring 17. The cover member 15 projects outwardly beyond theflange 14 and provides a peripheral flange 19 which seats on the cover20 for a tank (not shown) so that the housing depends into the tankchamber in a manner similar to that shown in FIG. 2 of the above patent.

A centrally located cylindrical bore 24 is formed within the housing 10and extends downwardly from the chamber 13 to a slightly smallercylindrical pumping chamber 25 formed in part by a tubular lower endportion 26 of the housing 10. An annular diflusor 30 is mounted on thelower end of the housing portion 26 and includes a bell-shaped portion31 having an inner surface 32 which curves uniformly from the innercylindrical surface of the housing portion 26 to a generally radiallyplane thereby defining an inlet 33 for the chamber 25. The difiusor 30also includes a series of four uniformly spaced stationary vanes 34which project radially inwardly from the inner curved surface 32 of thebell-shaped portion 31.

An outlet passageway 38 is formed within the housing 10 and curves atits lower end to intersect radially the upper end portion of the pumpingchamber 25. The upper end portion of the outlet passageway 38 is formedby a tubular portion 40 which projects upwardly through a hole 41 formedwithin the cover member and is sealed thereto by an O-ring 42. Asdisclosed in FIG. 3 of the above patent, the tubular portion 40 isconnected to the flush bowl by a suitable flexible e'lbow.

A reversible electric motor 45 has a lower flange 46 which mounts uponthe cover member 15 and is secured by a series of screws 47. The motor45 includes a drive shaft 50 which extends downwardly through thechamber 13, bore 24 and pumping chamber 25. The shaft 50 is Supported bysleeve-type bearing 52 retained Within a housing 55 having an upperflange 56 secured to the housing 10 by a series of peripheral screws 57.A flange 58 forms the lower end portion of the bearing retaining housing55 and has an external groove receiving an O-ring 61 and an internalcounterbore 62 receiving an O-ring 64 surrounding the shaft 50. TheO-ring 64 is retained within the counterbore 62 by an inverted cupshapedwasher 66.

An impeller 70 is mounted on the shaft 50 within the upper portion ofthe chamber 25 and includes a tubular hub portion 71 rigidly secured tothe shaft by a roll pin 72. The hub portion 71 has a lower curved nosesurface 73 and an upper frusto-conical or tapered surface 74. A singlevane 75 projects from the hub 71 and has a generally triangular orwedge-shaped cross-sectional configuration (FIG. 3). The vane 75 has twosurfaces 76 (FIG. 3) which are positioned transversely relative to theaxis of the shaft 50 in opposite directions and converge to form anupper radially extending edge 77. The lower end portion of each surface76 curves outwardly joining a flat base surface 78 to form parallelspaced leading edges 79.

A second impeller 80 is mounted on the lower end portion of the shaft 50and includes a hub portion 81 having a blind hole for the shaft andwhich is also secured to the shaft by a roll pin 72. The hub portion 81has a lower inverted dome-shaped end surface 83 and a tapered uppersurface 84 for streamlining the flow within the chamber 25. A singlevane 85 projects radially from the hub portion 81 and is constructedidentical to the vane 75. As shown, the lower impeller is positioned sothat its vane sweeps close to the vanes 34 of the diifusor 30 definingthe inlet 33, and upper impeller 70 is positioned so that its vane 75sweeps the bottom portion of the outlet 38.

The housing 10 further includes an inverted cup-shaped lower portionsurrounding the tubular portion 26 and which has a fiat bottom surface91 and an internal cylindrical bearing surface 92 concentric with thecylindrical pumping chamber 25. A cup-shaped filter 95, also preferablyformed of a rigid plastic material, includes an upper cylindricalportion 96 which seats for rotation on the surface 92 and includesinner-peripheral spur gear teeth 97. A peripheral flange 99 projectsoutwardly from the cylindrical portion 96 to provide a shoulder 100which seats on the lower surface 91. The flange 99 is received within acorresponding counterbore 102 formed within a retaining ring 104 securedto the lower surface 91 of the portion 90 by a series of peripheralscrews 106.

The filter 95 has a lower cylindrical portion having a series of axiallyspaced thin circumferential slots which divide the lower portion into acorresponding series of axially spaced rings 112. The rings 112 areintegrally connected by a series of four axially extending ribs 114which extend from the upper flange portion 99 to a flat circular bottomportion 115.

A vertically extending cavity is formed within the housing 10 andincludes an upper counterbore 122 and a lower counterbore 123. Anauxiliary drive shaft 125 extends through the cavity 120 and issupported at its upper end by a sleeve-type bearing 126 retained by anannular member 127 seated within the counterbore 122. A sleevetypebearing 128 is retained within the counterbore 123 and supports thelower end portion of the shaft 125. An O-ring 129 seals the lower endportion of the shaft 125 with the housing 10.

A spur gear is mounted on the lower end portion of the shaft 125 andengages the gear teeth 97 formed within the cylindrical portion 96 ofthe filter 95. Another spur gear 136 is rigidly mounted on the upper endportion of the shaft 125 and is driven through a gear train (not shown)by a pinion 138 mounted on the shaft 50 directly above an anti-frictionthrust bearing 139 seated on the upper end of the bearing retaininghousing 55.

A pin is secured within a hole 146 formed within the lower portion 90 ofthe housing 10 and extends downwardly parallel to the shaft 50. A seriesof generally triangular shaped scraper blades 150 have aligned holes forreceiving the pin 145 and are arranged in vertical spaced relation toproject inwardly into the corresponding slots 110. Each blade 150 isfree to slide or float on the pin 145 to prevent binding with theadjacent rings 112. The blades 150 are prevented from rotating on thepin 145 by a retaining member having a cavity 156 conforming to receivethe blades 150. The upper end portion of the retaining member 155 hasarcuate slot 157 which receives a correspondingly shaped rib 158projecting downwardly from the bearing ring 104 for positioning theretaining member 155 on the bearing ring and a screw 159 threaded intothe lower end of the pin 145 secures the retaining member.

In operation of the recirculating system of the invention, the motor 45reverses its direction of rotation for each cycle of operation from thatof the previous cycle causing the drive shaft 125 to reverse alternatelythe direction of rotation of the filter 95. As a result of theconstruction and speed relation of the vanes 75 and 85, the liquid whichis filtered through the slots 110 is pumped from the inlet 33 to theoutlet 38 in response to either direction of rotation of the shaft 50.Thus the impellers 70 and 80 cooperate to form a single direction axialfiow pump regardless of the direction of rotation of the impellers.

Referring to FIGS. 5-11 which show various embodiments and modificationsof a reversible single direction axial flow impeller constructed inaccordance with the invention, an impeller 165 (FIG. 5) includes atubular hub portion 166 having substantially the same configuration asthe hub portion of the impeller 70 shown in FIG. 3. A single vane 170projects radially from the hub portion 166 and has generally awedge-shaped crosssectional configuration similar to the vane 75 shownin FIG. 3. The vane 170, however, has a flat trailing lip portion 171 ofuniform thickness and which extends slightly transversely to the axis ofthe impeller to provide a flat surface adjoining a slightly curvedsurface 172 also extending generally transversely relative to the axisof the impeller. The opposite side of the lip portion 171 of the vane170 forms a flat surface adjoining a slightly curved surface 173 whichextends generally transversely to the rotatable axis of the impeller ina direction opposite to the surface 172. Thus in a manner similar to thesurfaces 76 of the impeller shown in FIG. 3, the surfaces 172 and 173are effective to produce a single direction flow regardless of thedirection of rotation of the impeller. The lip portion 171 aids inproducing a somewhat higher discharge pressure. 7

An impeller 175 (FIG. 6) includes a cylindrical hub portion 176 fromwhich two slightly curved vanes 178 project with the upper surfaces ofthe vanes extending transversely in opposite directions relative to theaxis of the hub portion 176. The vanes 178 are positioned so that theirlower leading edges 179 lie substantially within a plane extendingthrough the rotatable axis of the impeller. Thus when the impeller 175is rotated in opposite directions, the upper surfaces of the vanes 178function in the same manner as the vane surfaces 76 of the impeller 70or the vane surfaces 172 and 173 of the impeller 165, that is, toproduce a single direction flow of water.

A plastic impeller 185 (FIG. 7) includes a cylindrical hub portion 186having a pair of fiat integral ears 188 projecting radially to form alower base portion. A pair of generally triangular shaped flat vanes 190are formed integrally with the ears 188 of the hub portion 186 and areconnected to the corresponding ears 188 by thin web hinge sections 191so that the vanes 190 can pivot or tilt relative to the axis of the hubportion 186 in response to reverse rotation of the impeller 185.Preferably, the impeller 185 is constructed of polypropylene so that thehinge sections 191 will flex during long service without cracking ortearing.

A stop member or stud 192 projects from each side of each vane 190 andis adapted to engage the upper surface of the corresponding ear 188 tolimit the tilting movement of each vane 190 relative to the hub portion186. Thus when the direction of the impeller 185 is reversed, each vane190 tilts alternately to one of the positions indicated by the dottedlines and thereby alternately provides liquid propelling surfaces whichextend transversely in opposite directions relative to the rotationalaxis of the impeller.

A single direction axial flow impeller 195 (FIG. 8) has a cylindricalhub 196 which is secured to the shaft 50' by a cross pin 197. A collaror sleeve 198 seats on the upper end of the hub portion 196 and is freeto rotate between stops (not shown) relative to the shaft 50'. A pair ofdiametrically arranged pins 200 are rigidly secured to the lower endportion of the impeller hub 196 and a corresponding pair ofdiametrically arranged pins 202 are secured to the collar 198 inparallel spaced relation to the pins 200. A flexible vane 205,constructed of rubber or other flexible material, extends between eachcorresponding pair of pins 200 and 202. Thus when the direction of theshaft 50 is reversed, the collar 198 rotates on the shaft 50' betweenthe stops so that opposite sides of each vane 205 alternately provideliquid propelling surfaces which extend in opposite transversedirections relative to the axis of the shaft 50' and thereby propelwater in a single direction.

FIGS. 9 and 10 show an impeller 210 including a hub portion 211 having aconfiguration substantially the same as the hub portion of the lowerimpeller shown in FIG. 1. A pair of diametrically positioned fixed vanes212 of substantially uniform thickness project radially from the hubportion 211, and both vanes 212 have an axially extending flat portion214 which lie in a common plane offset radially relative to the rotaryaxis of the impeller. The flat portions 214 join corresponding flatcoplanar base portions 215 which extend transversely in oppositedirections relative to the rotational axis of the impeller. Thus theupper surfaces of the two fixed vanes 212 cooperate in a manner similarto the cooperation of the upper surfaces of the vanes 178 of theimpeller 175 (FIG. 6) to provide liquid propelling surfaces which extendtransversely in opposite directions relative to the rotational axis ofthe impeller and thereby provide a single direction axial flow impeller.

An impeller 220 (FIG. 11) includes a hub portion 221 having aconfiguration substantially the same as the hub portion 211 of theimpeller 210 (FIG. 9) but includes a single vane 222 having awedge-shaped crosssectional configuration similar to that of the vane 75of the impeller 70 shown in FIG. 3. The impeller 22, however, is formedby converging slightly curved walls each having a uniform thickness.Thus it becomes apparent that the vane 222 of the impeller 220 isessentially produced by moving the vanes 178 of the impeller 175 (FIG.6) closer together until the upper trailing edges of the vanes join.Therefore, from a functional standpoint, it is unnecessary for a singlevane to have a solid generally wedge-shaped cross-sectionalconfiguration as long as the vane provides at least two liquidpropelling surfaces which are positioned generally transversely inopposite directions relative to the rotational axis of the impeller.

Referring to FIG. 12 showing a modification of a recirculating systemconstructed in accordance with the invention, the housing 10 has a lowerend portion 26' which surrounds the lower impeller 80 and defines acircular inlet 33'. A filter includes a series of integrally formedradially extending dilfusor vanes 34' which project upwardly from thecircular bottom portion and are spaced slightly below the lower end ofthe housing portion 26. Although the vanes 34 rotate with the filter95', the vanes 34' function in the same manner as the vanes 34 (FIG. I),that is, to provide a smooth nonturbulent flow of liquid into the inlet33'.

From the drawings and the above description, it can be seen that aself-contained sewage unit having a recirculating system constructed inaccordance with the invention provides several desirable features andadvantages. For example, the construction and arrangement of theimpellers 70 and 80, and especially the position of a single generallywedge-shaped vane 85 adjacent the inlet 33 defined by the diffusor 30and the position of a single wedge-shaped vane 75 so that its leadingedges 79 sweep the bottom of the outlet 38, assures a high volume flowto the outlet 38 along with a quiet opera tion of the pump for eitherdirection of rotation of the shaft 50. The arrangement of the singlevane on each impeller and the orientation of the vanes has also beenfound to provide an equally high pumping efiiciency for either directionof rotation of the impellers.

The arrangement of the diffusor vanes 34 and 34' also provides animportant feature of the invention. That is, by employing a series ofradially extending vanes 34 or 34' which project inwardly adjacent thelower impeller 80, the flow of liquid into the inlet 33 or 33' is smoothand quiet with minimum turbulence so that the pump can operate with alow head of water surrounding the filter 95 or 95' without producingcavitation. While the diffusor vanes are especially effective when usedwith the impellers 70 and 80, it has been determined that the difiusorvanes may also be used with other impellers such as the screw-typeimpeller shown in the above patent for providing quiet operation andreducing cavitation of the pump when used with a low head of liquidwithin the tank.

The impeller modification shown in FIGS. -11 have been testedsuccessfully and found effective for pumping liquid always in onedirection from the inlet 33 to the outlet 38 in response to rotation ofthe impeller shaft 50 in either direction. The best combination ofoptimum performance and simplicity of manufacture, appears to be thearrangement of two axially spaced impellers each having a inglegenerally wedge-shaped vane such as shown in FIGS. 3, 5 and 11, with thevanes disposed in 180 relationship.

What is claimed is:

1. In a self-contained sewage system including a pump housing with meansdefining a chamber having an inlet and an outlet, an annular filtersurrounding said inlet and having a plurality of openings through whichliquid flows to said inlet, means on said housing supporting saidfilter, a plurality of wiper members extending into said openings, meanssupporting said wiper members on said housing, a main drive shaftrotatably mounted within said housing, a reversible motor connected tosaid drive shaft, and auxiliary drive means connected to said shaft andconnected to cause relative rotation between said filter and said wipermembers in response to rotation of said drive shaft in oppositedirections; the improvement comprising a reversible single directionaxial flow impeller including a hub portion mounted on said shaft withinsaid chamber, vane means projecting outwardly from said hub portion andproviding at least two different liquid propelling surfaces, one of saidsurfaces extending transversely in one direction relative to the axis ofsaid shaft and being effective to propel liquid axially of said housingfrom said inlet to said outlet in response to rotation of said shaft inone direction, and the other said surface extending transversely in anopposite direction relative to the axis of said shaft and beingeffective to propel the liquid axially of said housing in the samedirection from said inlet to said outlet in response to rotation of saidshaft in the opposite direction.

2. Apparatus as defined in claim 1 wherein said vane means include atleast one vane having a generally wedge shaped cross-sectionalconfiguration in a plane extending substantially parallel to the axis ofsaid shaft, and said vane having opposite sides forming said surfaces.

3. Apparatus as defined in claim 1 wherein said pump housing defines agenerally cylindrical chamber, said inlet disposed at one end of saidchamber, said outlet extending generally radially from the opposite endof said chamber, said impeller including vane means positioned forrotation adjacent said inlet and separate vane means positioned forrotation adjacent said outlet, and each said vane means providing saidtwo liquid propelling surfaces.

4. Apparatus as defined in claim 3 wherein each said vane meanscomprises a vane having a generally wedgeshaped cross-sectionalconfiguration in a plane extending substantially parallel to said shaft.

5. Apparatus as defined in claim 4 wherein said vanes are positionedsubstantially 180 from each other in relation to said shaft.

6. Apparatus as defined in claim 3 wherein said impeller comprises anupper impeller having a single vane positioned for rotation adjacentsaid outlet, and a lower impeller having a single vane positioned forrotation adjacent said inlet.

7. Apparatus as defined in claim 6 wherein said lower impeller includesa hub portion having a generally pointed lower end surface forstreamlining the flow of liquid into said inlet.

8. Apparatus as defined in claim 1 including a series of generallyradially extending ditfusor vanes positioned adjacent said inlet forproviding a smooth flow of liquid into said inlet.

9. Apparatus as defined in claim 8 including a bellshaped annularditfusor member surrounding said inlet and having an inner surfacecurving smoothly from an axial direction to a radial direction toprovide a smooth flow of liquid through said slots into said inlet, andsaid diifusor vanes projecting inwardly from said inner surface.

10. Apparatus as defined in claim 8 wherein said diffusor vanes areintegral with said filter.

11. In apparatus for use on a self-contained sewage system and includinga pump housing with means defining a chamber having an inlet and anoutlet, an annular filter surrounding said inlet and having meansdefining a plurality of axially space-d peripheral slots through whichliquid flows to said inlet, means on said housing supporting said filterfor rotation on its axis, a corresponding plurality of wiper membersextending into said slots, means connected to said housing andsupporting said wiper members, a drive shaft rotatably mounted withinsaid housing, a reversible motor connected to said drive shaft,auxiliary drive means connected to said shaft for rotating said filterin opposite directions in response to rotation of said drive shaft inopposite directions, and an impeller mounted on said shaft within saidchamber; the improvement comprising a plurality of generally radiallyextending ditfusor vanes formed integrally with said filter and disposedadjacent said inlet to avoid cavitation during operation with a low headof liquid surrounding said dilfusor.

12. In an axial flow pump including a housing defining a pumping chamberhaving an inlet and an outlet and a shaft rotatable in said chamber, animproved reversible single direction axial flow impeller comprising ahub p rtion mounted on said shaft within said chamber, vane meansprojecting outwardly from said hub portion, said vane means providing atleast two different liquid propelling surfaces, one of said surfacesextending transversely in one direction relative to the axis of saidshaft and being effective to propel liquid axially of said housing fromsaid inlet to said outlet in response to rotati n of said shaft in onedirection, and the other said surface extending transversely in anopposite direction relative to the axis of said shaft and beingeffective to propel the liquid axially of said housing in the samedirection from said inlet to said outlet in response to rotation of saidshaft in the opposite direction.

13. An axial flow pump as defined in claim 12 wherein said vane meansinclude at least one vane having a generally wedge-shapedcross-sectional configuration in a plane extending substantiallyparallel to the axis of said shaft, and said vane having opposite sidesforming said surfaces.

14. A pump as defined in claim 12 wherein said vane means comprises apair of diametrically opposed vanes mounted on said hub portion and eachsaid vane providing one of said liquid propelling surfaces.

15. A pump as defined in claim 14 wherein each said vane has asubstantially uniform wall thickness and includes a portion extendingsubstantially parallel to the axis of said shaft and a portion extendingtransversely to the axis of said shaft, and said transversely extendingportions of said vanes cooperatively providing said liquid propellingsurfaces.

16. A pump as defined in claim 12 wherein said vane means includes atleast one vane pivotally connected to said hu'b portion for movementbetween two transverse positions such that opposite sides of said vanealternately provide said liquid propelling surfaces in response torotation of said impeller in opposite directions.

17. A pump as defined in claim 16 wherein said im- 3,067,433 12/1962Dietz et al. 478 peller is formed of a plastic material and includes athin 3,288,294 11/ 1966 Frey 10393 web section integrally connectingsaid vane to said hub 3,342,341 9/1967 Lee 478 portion'of said impeller.3,356,221 12/1967 Katona et al. 478

18. A pump as defined in claim 12 wherein said vane 5 3,364,860 1/ 1968Matzen 1033 means include at least one flexible vane, and meansrotatably mounted on said shaft for supporting at least FOREIGN PATENTSa vane 678,531 1/1964 Canada.

593,633 5/ 1959 Italy.

References Cited 10 UNITED STATES PATENTS WILLIAM L. FREEH, PrimaryExaminer Couch 1033 Wade 103115 US. Cl. X.R. Fuqua 10393 15 478, 90;103-220 Morgan 103-93

